1. Field of Invention
The present invention relates to a securing structure, and method for securing, an energy absorber which is disposed on a compartment side of a structural member of a vehicle body, such as a pillar, a roof side rail, a header and the like, and which is covered with an interior trim material, such as a pillar garnish, a roof lining and the like. The energy absorber absorbs an impact energy transmitted thereto via the interior trim material.
2. Description of Related Art
In motor vehicles, particularly, in passenger cars, an energy absorber is disposed in a space between an interior trim member and a structural member of a vehicle body. Therefore, if an impact load is applied in a direction from the interior trim member to the structural member, the energy absorber deforms to absorb energy of the impact load. Normally employed energy absorbers are, for example, a grid rib member, a urethane pad, a steel member formed by bending a thin steel sheet so as to have a hat-like sectional shape, and the like. Also employed as an energy absorber is a generally-termed hybrid pipe (as described in U.S. Pat. No. 5,680,886) that is formed of a metal foil core member and sheets of a material other than metal that are laid on opposite side surfaces of the core member. In the hybrid pipe, the core member and the sheets on the opposite side surfaces of the core member are corrugated so that ridges and grooves alternate in a direction of an axis of the pipe.
A hybrid pipe, after being formed, can easily be changed into a desired sectional shape by correspondingly shaping the pipe. Furthermore, the energy absorption characteristic of a hybrid pipe can be adjusted by changing a dimension of the hybrid pipe measured between an outermost point in the curved outer surface of a ridge or protruded portion and an innermost point in the curved inner surface of a groove or recessed portion, that is the generally-termed apparent plate thickness of the hybrid pipe, or changing the pitch between adjacent protruded portions (recessed portions), and the like. Thus, a hollow-shaped energy absorber represented by a hybrid pipe or the like has properties desirable for an energy absorber.
Vehicle body structural members to be installed at certain locations in a vehicle body are formed into three-dimensionally bent shapes in order to meet strength requirements and design needs. To conform to the three-dimensionally bent shape of a structural member, a substantially straight-formed energy absorber is subjected to a bending process. Normally, the energy absorber bending process is time-consuming and disadvantageous in cost. Therefore, in some cases, a plurality of energy absorbers of the same sectional shape or dimensions are screwed, at opposite ends of each absorber, to a structural member, so that the energy absorbers function as a single unit.
In some other cases, the interval between a structural member and an interior trim material disposed at a compartment-side of the structural member, which interval is necessary to absorb a predetermined amount of energy, varies in the direction of a length of the structural member. In such a case, a plurality of energy absorbers of different sectional shapes or dimensions are screwed at opposite ends of each absorber to the structural member, so that the energy absorbers function as a single unit.
The aforementioned operation of securing a plurality of energy absorbers individually to a structural member is time and labor-consuming.
Accordingly, it is an object of the present invention to provide a securing structure that makes effective use of the properties of a hollow-shaped energy absorber, such as a hybrid pipe, and facilitates the securing of the energy absorber to a structural member.
According to an aspect of the invention, there is provided a securing structure including a plurality of hollow energy absorbers, and a joint member having fitting end portions which are fittable to end portions of at least two adjacent energy absorbers of the plurality of hollow energy absorbers, the end portions of the at least two adjacent energy absorbers facing each other, and the joint member being mountable to a vehicle body structural member.
In this securing structure, one of two fitting end portions of the joint member is fitted to an end portion of a first energy absorber of the at least two adjacent energy absorbers, the end portion of the first energy absorber facing a second energy absorber. The other one of the two fitting end portions of the joint member is fitted to an end portion of the second energy absorber, the end portion of the second energy absorber facing the end portion of the first energy absorber. By subsequently mounting the joint member, the energy absorbers are secured to the structural member so that the energy absorbers are ready for use.
The securing structure makes it possible to couple two adjacent energy absorbers by fitting an end of each energy absorber to a fitting end portion of the joint member and to secure the two energy absorbers coupled by the joint member to a structural member by mounting the joint member to the structural member. Therefore, the above-described securing structure eliminates the need to perform a so-called post-process on an energy absorber, for example, forming a securing hole, applying an adhesive, and the like, and enables easy and quick mounting of a plurality of energy absorbers to a structural member, thereby considerably improving the operability of the securing process.
The length of each fitting end portion of the joint member can be arbitrarily selected so as to prevent an energy absorber fitted to the joint member from slipping off from the fitting end portion of the joint member if the energy absorber is deformed by an impact load. Thus, a plurality of energy absorbers can be kept secured to the structural member even at the time of an impact. Therefore, if an energy absorber receives an impact load and another energy absorber subsequently receives an impact load, a sufficiently high energy absorbing function can be performed.
The facing end portions of the at least two adjacent energy absorbers may have cross sections that differ in at least one of size and shape, and each fitting end portion of the joint member may have a sectional shape substantially geometrically similar to a sectional shape of the end portion of an energy absorber to which the fitting end portion is to be fitted.
If the sectional shape of each fitting end portion of the joint member is substantially geometrically similar to the sectional shape of the corresponding energy absorber end portion as described above, the fitting end portions of the joint member can easily be fitted to the corresponding energy absorber end portions. Therefore, if energy absorbers that are to be disposed adjacent to each other and a joint member having fitting end portions each of which has a sectional shape substantially geometrically similar to the sectional shape of the corresponding energy absorber end portion are prepared beforehand, the energy absorbers can easily be coupled with high precision. Consequently, it becomes possible to provide a sequence of a plurality of energy absorbers coupled lengthwise wherein an energy absorber disposed at one site is different in sectional shape or size from an energy absorber disposed at another site.
In the above-described securing structure, the joint member may be formed by a structural body capable of absorbing an impact energy.
If the joint member itself is capable of absorbing impact energy as described above, even an impact load applied to the coupling portion between adjacent energy absorbers can be absorbed by deformation of the energy absorbers and the joint member therebetween. Therefore, a highly-efficient energy absorbing structure with continuity can be provided.
This structural body capable of absorbing impact energy may be hollow and may have a securing device provided in a surface that faces the structural member.
In this construction, since the joint member is hollow, it becomes possible to pass a wire harness, a duct or other accessories through the inner space of the joint member and the energy absorbers. Thus, the joint member and the energy absorbers also serve the protector function for the accessories extending therethrough. Furthermore, since the joint member is capable of absorbing impact energy, a highly-efficient energy absorbing structure with continuity can be provided. Further, the joint member can easily be mounted to a structural member by using the securing device provided in the structure body of the joint member.
In the hollow energy absorber securing structure according to the first aspect of the invention, the energy absorbers may include at least one hybrid pipe having a metal foil core and sheets laid on opposite surfaces of the core, each sheet being formed from a material other than metal. The hybrid pipe is formed by continually corrugating the core having the sheets on the opposite surfaces of the core in a direction of an axis of the hybrid pipe. The hybrid pipe and the joint member may be fitted to each other for a sliding movement in a direction of the axis.
Due to its property, the hybrid pipe elongates in directions of its axis while undergoing compression deformation, if the hybrid pipe receives an impact load in a direction intersecting the axis. In the above-described construction, the hybrid pipe and the joint member are fitted to each other in such a manner that they can slide in the directions of the axis. Therefore, if a hybrid pipe receives an impact load in a direction intersecting its axis and undergoes compression deformation, the elongation of the hybrid pipe in the directions of the axis is absorbed by a sliding movement relative to the joint member, so that another hybrid pipe adjacent to the joint member is not affected. As a result, if an impact load is subsequently applied to a different site, the hybrid pipe at that site performs the designed function to absorb impact energy.
The energy absorbers may include at least one metal pipe. The metal pipe and the joint member may be fitted to each other for a sliding movement in a direction of an axis of the metal pipe.
Due to its property, the metal pipe undergoes compression deformation and, simultaneously, bending deformation, if the metal pipe receives an impact load in a direction intersecting its axis. In the above-described construction, the metal pipe and the joint member are fitted to each other in such a manner that they can slide in the directions of the axis. Therefore, if a metal pipe receives an impact load in a direction intersecting its axis and undergoes compression deformation, the bending deformation of the metal pipe is absorbed by a sliding movement relative to the joint member, so that another metal pipe adjacent to the joint member is not affected. As a result, if an impact load is subsequently applied to a different site, the metal pipe at that site performs the designed function to absorb impact energy.
According to another aspect of the invention, there is provided a hollow energy absorber securing structure including a plurality of hollow energy absorbers, wherein at least two adjacent energy absorbers are connected by fitting an end portion of a first energy absorber of the at least two energy absorbers to an end portion of a second energy absorber of the at least two energy absorbers, the end portion of the first energy absorber and the end portion of the second energy absorber facing each other, and wherein at least one of the adjacent energy absorbers is mountable to a vehicle body structural member.
In this hollow energy absorber securing structure, at least two adjacent energy absorbers are connected to each other by fitting an end portion of one of the at least two energy absorbers to an end portion of another one of the energy absorbers, the end portions facing each other. Therefore this securing structure does not need a joint member, so that the number of component parts required can be reduced and a simplified securing structure can be provided. Furthermore, the energy absorbing characteristics of the end portions can be adjusted by changing the fitting length of the end portions facing each other.
In the hollow energy absorber securing structure described above, the at least two adjacent energy absorbers, except the end portions to be fitted, may have cross sections that differ in at least one of size and shape, and the end portion of the first energy absorber may be expanded or contracted so that the end portion of the first energy absorber has a sectional shape substantially geometrically similar to a sectional shape of the end portion of the second energy absorber.
Through this minor post-process on an energy absorber that has been formed so as to have a consistent sectional shape, the energy absorber can easily be coupled to another energy absorber.
According to still another aspect of the invention, there is provided a hollow energy absorber securing structure including a hollow energy absorber, and a resin-made member capable of absorbing an impact energy, wherein the resin-made member has an extended portion that is protruded from an end of the resin-made member and that is fittable to an end portion of the energy absorber. An end portion of the resin-made member is coupled to the energy absorber by fitting the extended portion to an end portion of the energy absorber mounted to a vehicle body structural member, so that the resin-made member is secured to the structural member.
In this hollow energy absorber securing structure, the resin-made member is coupled to the energy absorber by fitting the extended portion protruded from the end surface of the resin-made member to the end portion of the energy absorber, before or after the energy absorber is mounted to the structural member. Therefore, the end portion of the resin-made member is coupled to the energy absorber, whereby the resin-made member is secured to the structural member.
By fitting the extended portion of the resin-made member to the end portion of the energy absorber, the end portion of the resin-made member can be coupled to the energy absorber and secured to the structural member. Therefore, it becomes unnecessary to use a tapping screw or other securing device for securing an end portion of the resin-made member to the energy absorber or the structural member. Furthermore, since the resin-made member becomes tentatively secured when the end portion of the resin-made member is connected to the energy absorber, it becomes easy to position the resin-made member to the structural member. Thus, the operability after the coupling of the resin-made member and the energy absorber improves.
At the time of an impact load from diagonally downward, the resin-made member tends to globally bend upwards, and the rising of reaction load tends to delay until the bending deformation ends. In the invention, however, the extended portion of the resin-made member is fitted to and therefore restricted by the end portion of the energy absorber, so that the bending deformation of the resin-made member is reduced. Therefore, when an impact load is applied to the resin-made member, the reaction load immediately rises, so that a predetermined load-displacement energy absorbing characteristic can be achieved.
According to a further aspect of the invention, there is provided a hollow energy absorber securing structure including a hollow energy absorber and a resin-made member capable of absorbing an impact energy, wherein the energy absorber and the resin-made member form a sub-assembly by fitting an extended portion which is protruded from an end surface of the resin-made member that faces the energy absorber and which is fittable to an end portion of the energy absorber, to the end portion of the energy absorber, and by tentatively connecting the extended portion and the end portion to each other by a fixing device, and the sub-assembly is secured to the structural member.
In this hollow energy absorber securing structure, the sub-assembly of the resin-made member and the energy absorber formed by fitting the extended portion of the resin-made member to the end portion of the energy absorber, and tentatively connecting the extended portion and the end portion to each other through the use of the fixing device is secured to the vehicle body structural member. Therefore, the handling of the resin-made member and the energy absorber becomes easy, and the securing thereof to the structural member is further facilitated, in comparison with a hollow energy absorber securing structure according to a different aspect of the invention wherein an extended portion of a resin-made member is coupled to an end portion of an energy absorber, and the energy absorber is secured to a structural member
The aforementioned sub-assembly may be secured to the structural member by fastening a fasting device that extends through the end portion of the energy absorber and the extended portion of the resin-made member, to the structural member.
Since it becomes possible to fasten the resin-made member and the energy absorber to the vehicle body structural member by so-called joint fastening, the securing operation is facilitated. Furthermore, since the extended portion of the resin-made member is fitted to the end portion of the energy absorber, and then secured thereto by the fastening device, the resin-made member and the energy absorber can be firmly secured. Therefore, the bending of the resin-made member can be more effectively reduced.
The extended portion of the resin-made member may have a rib capable of absorbing an impact energy.
Provision of the energy absorption-capable rib in the extended portion of the resin-made member makes it possible to absorb impact energy that is applied to any site in the energy absorber, the resin-made member, and the coupling portion between the resin-made member and the energy absorber. Therefore, an efficient energy absorbing structure with continuity can be provided.
The structural member may include a front pillar and a roof side rail, and the energy absorber may be disposed at an intersecting portion between the front pillar and the roof side rail, and the resin-made member may be disposed at the roof side rail.
The energy absorber may be formed by one of a metal pipe and a hybrid pipe having a metal foil core and sheets laid on opposite surfaces of the core, each sheet being formed from a material other than metal, and the hybrid pipe being formed by continually corrugating the core and the sheets on the opposite surfaces of the core together in a direction of an axis of the hybrid pipe.
The interval between the intersecting portion between the front pillar and the roof side rail and an interior trim material is smaller than the interval between the pillar and a pillar garnish or the interval between the roof side rail and a roof lining. At the intersecting portion, therefore, a load-displacement energy absorbing characteristic with sharp reaction load rising and small displacement is required. This requirement is met by the hollow energy absorber formed by a hybrid pipe or a metal pipe, since either pipe has a characteristic with sharp reaction load rising.
According to a further aspect of the invention, there is provided an energy absorber including an elongated member, wherein a sectional shape of an end portion of the elongated member taken on a plane perpendicular to an axis of the elongated member is different from a sectional shape of a portion of the elongated member apart from the end portion thereof taken on a plane perpendicular to the axis, and wherein the elongated member is connectable to a vehicle body structural member.
According to a still further aspect of the invention, there is provided an energy absorbing structural body including a hollow energy absorber and a resin-made member capable of absorbing an impact energy, wherein the energy absorber and the resin-made member form a sub-assembly by fitting an extended portion which is protruded from an end surface of the resin-made member that faces the energy absorber and which is fittable to an end portion of the energy absorber, to the end portion of the energy absorber, and by connecting the extended portion and the end portion to each other by tentative fixing means.